1. Field of the Invention
This invention relates to electrical connectors and, more particularly, to card edge connectors having a grounding shield and a method of manufacturing the same.
2. Prior Art
In electrical arts it is a common practice to use a connector to mechanically and electrically couple a mother printed circuit board with a daughter printed circuit board as of the vertical edge card variety. In such a practice, there has been an evolution towards placing electrical contacts closer and closer together while maintaining a high, constant stress between the electrical contacts and the areas to be contacted. In placing the contacts closer together, as to 20 contacts per linear inch, the width of each contact must decrease. One such connector is found in U.S. Pat. No. 4,846,734, entitled "Vertical Edge Card Connectors" by Thomas G. Lytle which is assigned to the same assigned as herein and is incorporated by reference in its entirety herein.
There has also been developed a special type of connector which is known in the art as a bi-level connector; i.e.; a connector having two types of contacts that make contact with a daughter printed circuit board in two locations or at two levels. The two types of contacts are generally intermixed or alternatingly arranged in two opposing rows. The first type of contacts are arranged at a predetermined pitch, such as 100 mils, between the first type of contacts. The second type of contacts are also arranged at a predetermined pitch, such as 100 mils, between the second type of contacts such that there is a 50 mils pitch between the adjacent first and second contacts. One such connector is described in copending patent application Ser. No. 7/287,765, filed Dec. 21, 1988, now U.S. Pat. No. 4,934,961, entitled "Bi-Level Card Edge Connector and Method of Making The Same" by Piorunneck et al. which is assigned to the same assignee as herein and which is incorporated by reference in its entirety hereby. U.S. Pat. No. 3,399,372 to Uberbacher discloses a card edge connector having a plurality of thin sheet metal type ground contacts located between signal contacts. British Patent 1,048,062 discloses a connector having two flat side plates made of metal used to connect connector units into an assembly. U.S. Pat. No. 4,655,518 to Johnson et al. discloses a backplane connector having a daughter board connector element with contacts on the outside for grounding purposes and a backplane connector element with sidewall contacts.
One particular problem that has arisen with prior art card edge connectors is electrically induced magnetism or electromagnetism generated by electricity traveling through the contacts which can cause the undesired generating of electricity in adjacent contacts in the connector, also known as cross-talk. This undesired generation of electricity can cause false signals or degradation of true signals to be transmitted to the mother and daughter printed circuit boards. This obviously interferes with the proper utilization and reliability of such an assembly.
A further problem that has arisen with prior art card edge connectors is that daughter printed circuit boards have circuitry that needs to be grounded, preferably to the mother board at the same card edge connector as signals are transmitted through, such that only one connector is needed. However, by transmitting electricity through ground contacts in the connectors of the prior art, a relatively long travel distance or path was needed. These relatively long grounding paths in the prior art reduced switching time.
It is therefore an objective of the present invention to provide a new and improved connector and method of manufacturing the same that can overcome the above problems in the prior art as well as provide additional features and advantages.